Phytochemical profile, anti-glycation effect, and advanced glycation end-products protein cross-link breaking ability of Sclerocarya birrea stem-bark crude extracts

Sclerocarya birrea stem-bark is widely used for the treatment of many medical conditions. Advanced glycation end-products (AGEs) are implicated in the pathogenesis of vascular complications of diabetes mellitus. The study, other than phytochemical composition, evaluated the anti-glycation and AGEs-protein cross-link breaking effects of S. birrea stem-bark extracts.

Different S. birrea extracts and aminoguanidine (used as control) were incubated with bovine serum albumin (BSA) and glucose/fructose at 37oC for 40 days. Amounts of fluorescent AGEs (FAGEs) and immunogenic AGEs formed were determined. Anti-glycation activity percentage of each extract and aminoguanidine was calculated. Their AGEs-protein cross-link breaking abilities were also assessed. Standard techniques were employed for phytochemical screening. Volatile compounds were identified by means of gas chromatography mass spectrometry (GC-MS).

S. birrea stem-bark n-hexane extract was statistically more effective than aminoguanidine against the formation of total immunogenic AGEs (P<0.05). For FAGEs, ethyl acetate, methanol, and water extracts exerted significantly higher anti-glycation effects than aminoguanidine (P<0.001). Methanol extract exhibited the highest anti-glycation effect with an average IC50 value of 0.142 mg/mL against FAGEs. All extracts were effective in releasing BSA from the preformed collagen-AGEs-BSA cross-links. GC-MS enabled the identification of many biologically important compounds, including campesterol, stigmasterol, and 1-heptatricontanol.

S. birrea stem-bark has a potential for usage in the management of complications in uncontrolled glucose metabolism.